Device for detecting presence of a user for motor vehicle

ABSTRACT

The invention concerns a device for detecting the presence of a user to allow and/or prevent access inside a motor vehicle, the vehicle comprising at least a decorative element fixed to the body ( 2 ) proximate to an opening (O), the device comprising at least an electrode detecting ( 1 ) the presence of a user and a processing circuit ( 5 ) connected to the detecting electrode. The invention is characterised in that the decorative element (ED) has at least an electrically conductive part ( 12 ) coupled at least partly with the detecting electrode ( 1 ) so as to form an active detecting surface.

BACKGROUND OF THE INVENTION

1. Filed of the Invention.

The present invention relates to a device for detecting the presence ofa user in order to allow and/or prevent access to the inside of a motorvehicle.

2. Description of the Related Art.

Such detecting devices are already used within the scope of an accesssystem called a hands-free system in order to automatically trigger therelease of the door of a motor vehicle as the user approaches, withoutthe latter needing to use a key or a remote control. To carry out thisautomatic unlocking before opening the door, detection of the user isused to activate a remote exchange of data between an on-boardrecognition device on the vehicle and an identifier worn by the user.When the identifier is recognized as correct by the recognition device,the lock is released, thus allowing the user to open the opening leaf ofthe vehicle by grasping the handle. These known detecting devices aregenerally incorporated into the handles of the opening leaves of avehicle since the detecting action takes place prior to opening theopening leaf. Thus, it is known, in particular from document U.S. Pat.No. 6,075,294, to place the detecting electrode of a presence sensor ina handle.

However, in some cases, it may be desirable to incorporate a presencedetecting device directly into the bodywork of the vehicle. Thus, forexample, document FR 2 740 501 teaches the use of a presence sensor inthe rear of the motor vehicle around the trunk.

However, such a device requires fastening an additional casingcontaining the presence sensor to the bodywork.

One aim of the present invention is to provide a detecting device whichcan be placed in a preexisting decorative element on the vehicle.

This aim is achieved by the fact that the decorative element has atleast one electrically conducting part coupled at least partially to thedetecting electrode so as to form an active detecting surface. Thus, byvirtue of the present invention, this device does not require an extrapart to be added and fastened to the bodywork. This results in asubstantial reduction in the cost price of the detecting device.

According to a first embodiment of the present invention, theelectrically conducting part is coincident with the detecting electrode.

According to a second embodiment of the present invention, theelectrically conducting part comprises, on the one hand, the detectingelectrode and, on the other hand, a surface layer forming an offsetelectrode. In addition, an insulating part is inserted between thedetecting electrode and the false electrode so as to form a capacitor.

Thus, advantageously, this capacitor protects the treatment circuitagainst electrical overload.

According to a third embodiment of the present invention, the decorativeelement has a tongue and is completely covered with a surface layerforming an offset electrode. The electrically conducting part comprises,on the one hand, the detecting electrode and, on the other hand, theoffset electrode. A second insulating part is inserted between thedetecting electrode and the offset electrode in order to form acapacitor. Thus, the detecting electrode and the electronic processingcircuit are placed inside the vehicle so that the electrical wireconnecting the electrical components of the detecting device isinaccessible from outside the vehicle. Consequently, the risk of theftof the vehicle by creating a short circuit in the electrical system issignificantly decreased.

Advantageously, the device according to the present invention has thefollowing features:

-   -   the offset electrode is formed by a layer of electrically        conducting paint.    -   the capacitor has a capacitance of around ten picofarads.    -   the insulating part comprises a layer of plastic or of rubber.    -   the electrically conducting part is electrically insulated from        the bodywork by a first insulating part.    -   the thickness of the first insulating part is greater than about        1 mm.    -   a closed housing, sheltered from water, is made in the first        insulating part and designed to accommodate the electronic        processing circuit. Thus, advantageously, it is not necessary to        fasten an extra casing containing the processing electronics to        the bodywork.    -   the detecting device is formed by a touch-sensitive capacitive        sensor such that the decorative element forms a clearly defined        touch-sensitive surface. Thus, by virtue of this device, the        user easily identifies the region for controlling the        locking/unlocking of the locks and/or the opening/closing of the        doors.    -   the decorative element is in the form of a logo representing the        make of the vehicle manufacturer, the model of the vehicle        and/or the identity of the manufacturer. Thus this device has an        esthetic appearance.    -   the detection of a user is confirmed by the emission of a sound        and/or light signal.    -   the opening leaf is a trunk or a rear hatchback.

Moreover, it has been shown that integrating a sensor, consisting ofdetecting electrodes and an electronic processing circuit, in thebodywork presents many problems and especially that of false detections.These false detections arise, on the one hand, from significant exposureof the sensor to bad weather and, on the other hand, from interferencedue to the proximity of the sensor electrodes with the metal bodywork ofthe vehicle. In fact, bad weather (water, snow and other damp elements)causes false detections, which can be detrimental to the properoperation and to the reliability of the device.

A second aim of the invention is therefore to eliminate these drawbacksby providing a touch-sensitive detecting device which can be positioneddirectly on the vehicle bodywork while at the same time having improveddetection reliability.

To this end, according to a variant embodiment of the present invention,the decorative element and/or the detecting electrode has, in crosssection, sloping faces promoting the removal of water. Thus, by virtueof this structure, the touch-sensitive detecting device is positioneddirectly on the vehicle bodywork.

Preferably, the insulating part has at least one part forming a waterchannel so as to promote the removal of water.

Preferably, the insulating part forms a water channel and is made in theform of a groove made in the layer.

Advantageously, the first layer has an upper thickness of about 1 mm.

The touch-sensitive detecting device is advantageously used, within thescope of a hands-free access system, after prior identification of theuser, in order to control functions:

-   -   of locking and/or of unlocking the opening leaves of the        vehicle, after prior identification of the user, in the case of        a hands-free access system,    -   of opening and/or of closing especially for the trunk.

Other features and advantages of the invention will become furtherapparent from the following detailed description. This description,which is purely illustrative and nonlimiting, relates to the exemplaryembodiments described with reference to the appended figures, amongwhich:

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a perspective view of a motor vehicle equipped, around thetrunk, with a detecting device according to the invention,

FIG. 2 shows a partial side view of a motor vehicle equipped, around adoor, with a detecting device according to the invention,

FIG. 3 a shows, in longitudinal section, a first embodiment of thepresent invention, in which at least part of the decorative elementforms the detecting electrode,

FIG. 3 b shows a second embodiment of the present invention, in whichthe decorative element has a surface layer forming an offset electrode,

FIG. 4 presents a third embodiment of the present invention in which theelectrode and the electronic processing circuit are fastened inside thevehicle,

FIG. 5 shows a fourth embodiment of the detecting device according tothe invention, in which the electronic processing circuit is placed inthe decorative element,

FIGS. 6 a, 6 b and 6 c have, in side section, several possiblestructural shapes for the detecting device.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

In FIG. 1, a user U close to a motor vehicle V and facing an openingleaf O of the vehicle, in this instance the trunk, is ready to touchlightly on a decorative element DE positioned on the bodywork, forexample at the center of the strip of the trunk. This decorativeelement, according to the invention, forms a presence sensor C1 of thetouch-sensitive sensor or approach sensor type. This type of sensormakes it possible to detect contact by the user or the approach of auser in order to activate and/or control a given function. This sensorcomprises an electrode for detecting a user and an electronic processingcircuit connected to the electrode.

The decorative element DE shows a distinctive sign of the make of thevehicle or of the manufacturer and is positioned directly on thebodywork. Thus, the decorative element DE may take both diverse andvaried shapes, namely geometrical, circular, etc. shapes, which mayrepresent letters, figures, signs, etc. These various shapes form logosor pictograms representative of the make, of the model of the vehicleand/or of the identity of the manufacturer.

FIG. 2 shows another placement of a decorative element DE on the vehiclein which a presence sensor is incorporated. In this representation, thedecorative element DE is positioned on an opening leaf O, in this case adoor, of a vehicle close to the location of the handle P of the door.The detection of contact by or the approach of a user by means of thesensor C1 via its detecting electrode may be combined with an audiblewarning so that the user is aware that he has clearly been detected.Thus, a characteristic sound is emitted on each detection.

As a variant or simultaneously, illumination of the decorative elementmay be provided in order to warn the user that he has been detected.This illumination may be achieved especially by means of an LEDincorporated into the decorative element DE or into another elementclose thereto.

The integration of the sensor C1 into the decorative element DE makes itpossible to avoid creating a new location on the handle or on thebodywork, or else on the trunk or doors of the vehicle. This is veryeconomical since there is no extra piece to be added.

The presence sensor may be used for activating and/or controlling thevarious functions and especially in systems referred to as hands-freeaccess and/or starting systems. Thus, the following may be used:

-   -   as approach sensor, as soon as the user lightly touches the        sensor, in order to activate remote data exchange between a        recognition device consisting of a central control unit onboard        the vehicle and an identifier worn by the user. When the        identifier is recognized as correct by the recognition device,        the lock is released, and the user may open whichever opening        leaf he desires,    -   as element for controlling the locking of an opening leaf, the        locking taking place after the portable identifier worn by the        user has been recognized as correct. Specifically, after having        left his vehicle or after having put certain objects in his        trunk, the user may wish to carry out a deliberate action in        order to lock his vehicle. The detecting device according to the        invention may be used for this purpose. Thus, in the case of a        trunk, when the user grasps his trunk in order to pull it down,        he lightly touches the presence sensor and directly controls the        locking of his trunk by means of a smooth movement.    -   as control element for opening or closing an opening leaf such        as the trunk. In fact, at present, the trunks of some vehicles        are provided with mechanisms allowing the automatic opening        and/or closing of the trunk. These mechanisms operate mainly by        means of motors but it is necessary to prevent them being        inadvertently started. Thus, the presence sensor makes it        possible to control the opening or the closing of the trunk        after the prior recognition phase and possibly the unlocking        phase have taken place. The detection for activating the initial        data exchange may be carried out by the same presence sensor or        by other means, for example an approach sensor or a        touch-sensitive sensor positioned on a handle. When the same        presence sensor is used, a time delay may be provided in order        to distinguish the two control types.

It should also be noted that the sensitivity of the presence sensor isset to allow the detection of user contact when the latter wears gloves,which is often in winter.

FIGS. 3 a and 3 b show, in longitudinal section, two structures of thedetecting device according to the invention. These structures allowoperation, with a limited number of false detections, when the electrodeis positioned on the bodywork of a motor vehicle. These configurationsespecially consist in removing the contact of the electrode with themetal present around and under it.

The representations 3 a and 3 b of the electrode and of the sensor afterincorporation into a decorative element are representations inlongitudinal section, the shape of the decorative element being veryvariable and mainly dependant on the manufacturer. In these figures, theelectrode 1 is insulated from the metal surface of the bodywork 2 bymeans of a first insulating layer 3 forming a support element for theelectrode. This first layer of insulator makes it possible to preventthe electrode coming into contact with the ground, formed by the vehiclebodywork. The first insulating layer 3 is preferably a plastic such as arubber or a Teflon (registered trademark), and has a thickness whichvaries with the decorative element in which the sensor is incorporated.This thickness is generally greater than 1 mm and may be as high as 1cm.

The electrode 1 and the first insulating layer 3 are kept fastened byclipping or adhesive bonding. The electrode 1—insulating layer 3assembly, forming all or some of the decorative element DE, is held onthe bodywork 2 via fastening means 6. These fastening means may beadhesive, screws, rivets or any other means allowing the decorativeelement to be held on the bodywork.

In some cases, especially when the decorative element is large or whenit has a particular shape in its center, it may be desirable that onlypart of the decorative element has the functionality of a detectingdevice. Thus, the detecting electrode of the touch-sensitive sensor C1will only be formed by part of the decorative element.

In other situations, the electrode 1 of the sensor will be formed by thewhole of the decorative element.

According to the present invention, the decorative element DE has atleast one electrically conducting part 12 coupled at least partiallywith the detecting electrode 1 in order to form an active detectingsurface. The surface for detecting the approach by or contact with theuser is called the active detecting surface. For example, when thepresence sensor is a touch-sensitive sensor, the active surface consistsof part or all of the outer surface of the decorative element.

The electrode 1 is connected, via a connecting wire 4, preferably formedby a coaxial cable crossing the first insulating layer 3 and thebodywork 2, to an electronic circuit 5 for processing data detected bythe electrode 1. The electronic processing circuit 5 is positioned inthe vehicle, in the trunk, or in the passenger compartment of thevehicle. It is connected to a management and control unit 9 of thehands-free system, positioned in the passenger compartment. Thismanagement and control unit enables the lock of at least one vehicleopening leaf O to be controlled electronically.

According to a first embodiment of the invention, shown in FIG. 3 a, theelectrically conducting surface of the decorative element DE iscoincident with the detecting electrode 1. In this case, theelectrically conducting part 12 is coincident with the detectingelectrode 1. The latter forms both the electrically conducting part 12and the detecting electrode. Thus the system for accessing the vehicleis triggered by approaching or touching this detecting electrode 1.

According to a variant (not shown), only part of the decorative elementforms the detecting electrode. An insulating layer covers the rest ofthe electrode 1. In this case, presence detection is obtained bytouching or approaching the uncovered part of the electrode.

However, such a detecting device may be quickly damaged. This is becausethe electrode is directly exposed to rain and dirt. Furthermore, thisdetecting device may be subjected to an electrical overload.Specifically, a user touching the electrode 1 with the ends of chargedfingers applies a voltage to the processing circuit which can reach 25kV. The processing circuit 5 generally used in such a device does notwithstand such high voltages.

FIG. 3 b shows a second embodiment of the invention making it possibleto overcome these drawbacks. According to this variant, the decorativeelement DE comprises a detecting electrode 1 inserted between a firstand a second insulating part 3, 7. Furthermore, the decorative elementDE is covered with an electrically conducting layer 12 forming a falseelectrode or offset electrode 8 on the surface of the second insulatinglayer 7. This offset electrode 8 constitutes, with the detectingelectrode 1, a capacitor which protects the electrical circuits of thedevice against any electrical overload.

Advantageously, this capacitor has a capacitance of about tenpicofarads. The insulating parts 3, 7 may consist of layers of air,plastic or rubber.

The offset electrode 8 may, for example, be formed by a layer of paintcontaining electrically conducting elements.

FIG. 4 shows a third embodiment of the invention. According to thisembodiment, the decorative element DE comprises a conducting tongue 14and is covered with an electrically conducting layer, such as a paint.

The conducting tongue 14 of the decorative element DE is capable ofbeing placed in an opening of the bodywork 2. A T-shaped insulatingelement 3 is placed between the bodywork 2 and the decorative elementsuch that the latter is completely insulated electrically from thebodywork 2. The end of the tongue 14, placed inside the vehicle,supports a second insulating part 7, for example made of plastic orrubber. A detecting electrode 1 is fastened to the insulating part 7 soas to form, with one face of the conducting tongue 14, a capacitor. Thusthe capacitor protects the whole electric circuit of the device againstelectrical overloads.

Alternatively, the detecting device may comprise two detectingelectrodes 1 fastened on each side of the tongue 14 such that itssensitivity is improved.

According to a variant (not shown), the insulating part 7 consists ofair. Thus, the detecting electrode 1 is fastened at some distance fromthe conducting tongue 14.

Advantageously, according to this embodiment, no electrical wire isaccessible from the outside of the vehicle such that an ill-intentionedperson desiring to steal the vehicle is prevented from short-circuitingthe electrical system.

Preferably, the tongue 14 consists of the tongue for gripping thedecorative element DE when it is painted. Thus, advantageously, if thevehicle already comprises a painted decorative element, it is notnecessary to alter the molds for manufacturing the latter.

According to a variant embodiment of the present invention, thedetecting electrode 1 and the decorative element DE have sloping facesfavoring the removal of water.

FIGS. 6 a, 6 b and 6 c show, in cross section, several possible shapesof the decorative element. The insulating part 3, inserted between theelectrode 1 and the bodywork 2, makes it possible to prevent directcontact between the electrode and the bodywork, which would causeinterference and hamper the detection. The insulating part 3 may havevarious shapes. However in all these cases, this shape must favor theflow of drops of water in order to prevent the latter stagnating in theenvironment close to the electrode 1. For example, the insulating part 3of the embodiment shown in FIG. 4 forms a channel allowing the removalof water.

The choice of insulator varies according to certain restrictions such asresistance to bad weather, for example. Thus, this insulator may beTeflon (registered trademark), rubber or another plastic.

In FIG. 6 a, the first insulating part has, in cross section, atruncated triangle shape and is positioned in the extension of theelectrode. The water therefore flows down to the bodywork via theelectrode and the first insulating layer 3. The bodywork, with a paintedsmooth surface, then allows the complete removal of water.

In FIG. 6 b, the first insulating part 3 has two elements: a firstelement of truncated triangular shape in section and a second element ofrectangular shape. This rectangular-shaped element has complementarymeans for removing water formed by the presence of water-removinggrooves 11. These grooves are located mainly on the periphery of thesecond element of the rectangular-shaped insulator.

FIG. 6 c shows another possible shape of the insulator. According tothis embodiment, the first layer of insulator 3 is of circular orrounded shape.

The combination of the shape of the electrode, the shape of the firstinsulating layer and of complementary water-removal means always leadsto a structure making it possible to optimize the water removal from thesurface of the electrode and/or from the environment thereof.

The electronic circuit for processing data collected by the electrode isa commercial circuit operating by detecting a variation of capacitancebetween the electrode and the ground of the vehicle. Some modificationson the electronic processing circuit of the sensor are needed dependingon whether it is desired to increase the sensitivity to allow detectionwith gloves or to decrease the sensitivity to decrease the inopportunedetections. The insertion of an additional electronic component such asa resistor or capacitor between the electrode and the processing circuitmakes it possible to achieve a compromise between these two situations.

FIG. 5 shows a fourth embodiment of the present invention. When thefirst layer of insulator 3 is thick enough and when the decorativeelement DE is detached a little from the bodywork, a closed housingsheltered from water can be created inside the first layer 3. Thishousing may incorporate the electronic processing circuit 5 which isthen positioned outside the vehicle, as shown in FIG. 5. The electronicprocessing circuit, which is very small, a few cm², is then surroundedwith insulator and becomes completely sheltered from bad weather. Aconnecting wire 10 connected to a management and control unit 9 of thevehicle makes it possible to transmit the information from the sensor inorder to activate and/or control the desired function.

1. A device for detecting the presence of a user in order to allow and/or prevent access to the inside of a motor vehicle, the vehicle comprising at least one decorative element fastened to the bodywork (2) close to an opening leaf (O), the device comprising at least one electrode (1) for detecting the presence of a user and a processing circuit (5) connected to the detecting electrode, wherein the decorative element (DE) has at least one electrically conducting part (12) coupled at least partially to the detecting electrode (1) so as to form an active detecting surface, the decorative element (DE) has a tongue (14) and is completely covered with a surface layer (8) forming an offset electrode, the electrically conducting part (12) comprising, the detecting electrode (1) and, the offset electrode (8), and in that a insulating part (7) is inserted between the detecting electrode (1) and the offset electrode (8) in order to form a capacitor, the detecting electrode (1) and the electronic processing circuit (5) being placed inside the vehicle so that the electrical wire (4) connecting the electrical components of the detecting device is inaccessible from outside the vehicle.
 2. The detecting device as claimed in claim 1, characterized in that the offset electrode (8) is formed by a layer of electrically conducting paint.
 3. The detecting device as claimed in claim 1, characterized in that the capacitor has a capacitance of around ten picofarads.
 4. The detecting device as claimed in claim 1, characterized in that the insulating part (7) comprises a layer of plastic or of rubber.
 5. The detecting device as claimed in claim 1, characterized in that the electrically conducting part (12) is electrically insulated from the bodywork (2) by a second insulating part (3).
 6. The detecting device as claimed in claim 5, characterized in that the thickness of the second insulating part (3) is greater than about 1 mm.
 7. The detecting device as claimed in claim 5, characterized In that a closed housing, sheltered from water, is made in the second insulating part (3) and designed to accommodate the electronic processing circuit (5).
 8. The detecting device as claimed in claim 5, characterized in that the second insulating part (3) has at least one part forming a water channel so as to promote the removal of water.
 9. The detecting device as claimed in claim 8, characterized in that said part forming a water channel is made in the form of a groove (11) made in said first part (3).
 10. A device for detecting the presence of a user in order to allow and/or prevent access to the inside of a motor vehicle, the vehicle comprising at least one decorative element fastened to the bodywork close to an opening leaf, the device comprising at least one electrode for detecting the presence of a user and a processing circuit connected to the detecting electrode, wherein the decorative element has at least one electrically conducting part coupled at least partially to the detecting electrode (1) so as to form an active detecting surface, and the detecting device makes it possible to control the opening and/or closing functions of an opening leaf, after prior identification of the user.
 11. A device for detecting the presence of a user in order to allow and/or prevent access to the inside of a motor vehicle, the vehicle comprising at least one decorative element fastened to the bodywork proximate an opening leaf, the device comprising at least one hands free detecting electrode detecting the presence of a user without use of a key or remote control and a processing circuit connected to the detecting electrode, wherein the decorative element has at least one electrically conducting part coincident with the detecting electrode so as to form a single active detective surface.
 12. The detecting device as claimed in claim 11, further comprising a surface layer forming an offset electrode, and a first insulating part disposed between the single active detective surface and the offset electrode so as to form a capacitor.
 13. The detecting device as claimed in claim 12, wherein the offset electrode is formed by a layer of electrically conducting paint.
 14. The detecting device as claimed in claim 12, wherein the capacitor has a capacitance of around ten picofarads.
 15. The detecting device as claimed in claim 12, wherein the first insulating part comprises a layer of plastic or of rubber.
 16. The detecting device as claimed in claim 12, wherein the single active detective surface is electrically insulated from the bodywork by a second insulating part.
 17. The detecting device as claimed in claim 16, wherein a thickness of the second insulating part is greater than 1 mm.
 18. The detecting device as claimed in claim 12, characterized in that the single active detecting device is formed by a touch-sensitive capacitive sensor such that the decorative element forms a clearly defined touch-sensitive surface.
 19. The detecting device as claimed in claim 12, wherein the decorative element has, in cross section, sloping faces promoting the removal of water.
 20. The device according to claim 12, wherein the detecting device makes it possible to control locking and/or unlocking functions of the opening leaves of the vehicle, after prior identification of the user.
 21. The hands-free access and/or starting system as claimed in claim 11, wherein the detecting device makes it possible to control the opening and/or closing functions of an opening leaf, after prior identification of the user. 